Lifting jack construction



L. SCHWEITZER LIFTING JACK CONSTRUCTION Nov 6, 1951 2 SHEETS SHEET 1Filed Jan. 16, 1950 INVENTOR.

100/5 JCHWf/TZZK 1951 L. SCHWEITZER LIFTING JACK CONSTRUCTION Filed Jan.

, 2 SHEETS-SHEET 2 INVENTOR.

100/5 JCHWf/TZZR BY Qaflk- 4 ATTO/F/Vf J Patented Nov. 6, 1951 FNIiiO"IE w "Y LIFT ING .ifnf'on ooNsTntJorIoNf Louis Schweitzer,- Royal Oak,Mich, assignor to Motor Products Corporation, Detroit,'Mich., a i

corporation'of NewYorks' v Application January 1s, 1950,SerialNoI138,905

This invention relates to lifting jacks and refers more particularlyjtoimprovementsiin jacks of the type used in' connection with road vehiclesfor raising a selected ground engaging wheelgf It is an object of thisinvention to provide a light weight jack capable'of lifting substantialloads with no danger to inexperienced-users and composed ofarelativelyfew simple parts capable of being inexpensively manufacturedand asse'mbled. f

The simplicity; ease and safety of'operat ion of the jack is due largelyto the use of sliding wedge typelocking devices inpl'ace of the usualratchet or rackand gear typesof lifting mechanisms. In accordance withthis invention, at least two wedgetypelocking devices operate-"inconjunction withone'a'nother te elevate the lift and cooperate tosecurely hold-the lift inany one of its raisedpos'itijons, i

It is afurther object of this invention to provide a jack of theabovetype' wherein the wedge devices are alternatively moved upwardly byan arm to raise the jack lift step by step and'wherein provision is madefor releasing the wedge devices to permit lowering of'the'lift withoutmanipulating the'arm." As a 'result, the jack may be lowered'with easeand the danger of'thearm striking the user is avoided. v The foregoingas wellas other objectswill be made more apparent'as thisdescriptionproceeds especially when considered in connection with the accompanyingdrawingswhereinz' Figure l'is'a" side elevationalview of a weightlifting "jack embodying the features of this inven- Figure 2 is alongitudinal' -sectional view through the lower portion-of -the-jack;--

" Figure 3 is'an enlarged vertical 'se ctional' -view through apartoffthe jack-shown in Fig-urel;

Figure 4 is a sectional view taken onthe line 4-4 of Figure 2; 1

' Figures 5' and-6 are sectional views taken respectively inthe lines5-5 and 6-6 of Figure 4.

Figure 7 is a sectional view taken on the line 1- -1'ofFi'gure5 The jackselected herein for the purpose of "illustration is especiallyadaptedfor the purpose of raising oneor more of the ground engaging wheels of a-road vehicle and the nature-ofthe operating mechanism renders the jackhighly suitable for applications wherein a substantial strokeor-movement of the elevating part is required such, for example,=as isthe case withsocalled bumper jacks.=

- I The lifting-jack shown in-Figures Land 2 or ape rturedto receive asocket l5. The socket l5 I '8Claims." (Cl. 254-106) is open'at the topand has a-lateral flange 16 which overlaps the top surface of theelevated base portion M.- A slot I1 is formed in one side of the socketI5 and a resilient strip'l8 extends across the slot'at the outer side ofthe socket. The upper end of the strip is secured in place by the flange[6 and the lower end of the strip crimped around the'bottom-edge of thesocket. The resilient strip is bent intermediate the ends to providealoop l9 which projects into the socket 15throughthe-slot l1.

' The column Ii is also preferably formed of sheet metal and is shown inFigure 4 of the draw ings'as being channel-shaped in cross section. Theopposite side walls- 20- and 21 of the-column are provided withlaterally inwardly projecting flanges-22 which terminate short ofone'another to provide a longitudinally extending slot 23 therebetween;Also, the flanges 22 cooperate-with the remaining portions of the-columnto form a-vertically extending guideway 24.

tioned to register with the slot I! and to receive the loop 19 of theresilientstrip la in' the assembled position offthe column with respectto the socket. The loop 19 of the spring lBprovides a resilient detentfor removably holding the column ll in'a'vertical position on the baseI0." The elevating part I2 is shown in the several figures of thedrawingsa's comprising a pairof elongated channel-shaped sections 26positioned with the channels opening toward one another and of a size toreceive the vertical column 20, as shown in Figure 4 of the drawings.The sec,'- tions 26 are secured in assembled relationship by a pad orsupport 2'! in the form of a sheet metal stamping. The pad 21 is shownin Figures land 2 of the drawings as extending laterally with rel-.spect to the column and as having laterally spaced projections 28 attheinner end. The pro- .J'ections 28 are shown'in Figure-4 of thedrawings of a vehicle to lift the same when required.vv The liftingmechanism l3 comprises an operating memberv 23, a :pair of lockingdevices 30...;and

3i. anda releasing member 32. Thelockin'g devices 36, 3|. are slidablysupported. withinlthe guideway 24 and it will be noted'from FiguresZ and5 of I the drawings that the device 30 is supported in the guidewaydirectly above the device 3l.

The locking device 30 is provided with a pair of wedgesi33and'34slidably supported one above the other within the guideway 24. Theadjacent ends of the wedges are inclined in a direction extendingtransversely to the guideway .24 and pro vide overlapping surfaces 35and 36 on there'- spective wedges.

The locking device 3! also comprisesa pair. of wedges3l and 38 slidablysupported within the guideway 24 with the wedge 3! positioned above thewedge 38 in vertical alignment with the lat-' ter. 3'! and 38 areinclined with respect to the guideway 24 to provide overlapping suriaoes39 and 49 on the respective wedges. As shown particularly Figure of thedrawings, the'two pairs of wedges are similar inconstruction but arerelatively positioned so that the overlappingsurfaces 39 and 48 on therespective wedges 31 and 38 are inclined in a directionopposite thedirection ofinclination of the corresponding surfaces on the wede sfi ashown in Figure 7 of the drawings .the opposite ends of the springs 4|areturned laterally and respectively project into elongated slots formedthe wedges of each pair 35 and 3|. '1he ;springs 4l merely-serve as tiesbetween the respective wedges inithe pairs 30 and 3| in order permitmovement of the wedges in each pair as a unit in an upward direction.The strength 7 of the springs 41 is not sufficient to cause jam-Themtermaiate' portion 43 of 'the'strip' con- 7 tiniies downwardlyalongth'e' inner surface of the side Hand is extended betwe'en' theoverlapping surfaces '39' and 40 of the wedges 37 and 38. "The lower end44 of the'strip continues downwardly Talo'ngthe inner "surface of theside 20 to a point adjacent the bottom of the column'wherein it's'ecuredto'the column. The upper'end of the flexible strip 'extendsfora substantial distance abovethe'locking device""30 and-"is also-securedto the column. "Attention is called to the factthatthe intermediateportion 43 of the flexible member or strip is notfastenedtotheadjacentside of the guideway-24 and as-a consequence does not inter 'fere withtherequired-movement of thewedges. The-purpose of the flexible-memberisto hold the wedges in frictionalcontact with the sides of theguideway-24 so that only a slight relative movement of the wedges ofeitherlocking device towardone anotheris suflicient to cause .jammingof thewedges against adjacent sides of the guideway 24.

The above. arrangement is such that whenthe force is applied in anupwarddirectionlto the wedge 33, the overlapping .or .wedging surface. 35 ismoved away from the coacting. surface 36 on the lowermost .wedge34sothat both wedges 33 and 34 maybe readily moved in an upward .direction.within the guideway 24. Thisis also true of .the .second pair of wedgesof. the locking the adjacent bottom wedges.

4 device 3!, although the two pairs of wedges are independently movablealong the column.

Adownward force applied to the uppermost wedge of each paircauses thesewedges to move relative to the guideway 24 in a direction toward Theslots into which the laterally turned ends of the springs 4| 7 "projectare of sufficient size to permit the required movement of the top wedges33, 31 toward wed'ging'faces 35', 39011 the respective top wedges Theadjacent end portions of the wedges 33,31 press against the adjacentportion of the flexible strip 42 and apply a laterally outward forcecomponent against the oblique wedging surfaces 36,10 of thebottomiwedges 3.4 an-d38 respectively. Thus the wedges of each pairareshifted laterally outwardly and are jammed against the adjacent sides ofthe guideway 24. In other words, the .wedges of each pair becomefrictionally locked against further downward movement relative 'to theguideway'24.

Releasing ofthe wedges may bev readily accomplished by merely applying adownward force on the lowermost wedges of each pair. This application offorce moves the lowermost wedges downwardly'slightly relative 'to theuppermost wedges andenables. the .locking'd'evices to be freely moveddownwardly'in the guideway 24. This releasing action is accomplishedinthe present instance by .manipulating the member 32 which will' bepresentlydescribedin detail.

As shown'in Figures 1 to 3inclusive, the wedge 33 is provided with alateral "outwardly. extending projection 45 and the wedge3l is providedwith a similar'projection 4.6. The projections '45 and 46 extend throughthe slot23 in the column 1i and also respectively project throughelongated slots 41 andfi lfo'rmedfin the lifting device 12. The wedges3'4 and 38 are respectively provided with lugs 49 mate; These lugsalsofextend through the slot 23 the column 'I l and respectivelyprojectthrough s1ots.5l and52 formed in the adjacent wall of"theflifting part l2.

The operatingmember 29 has a socket part 53 shaped at sneienaw slidablyreceive a suitable tool 54 and having the other endconnected to theprojection 45 by pivot pin 46'. in a manner to enable swinging movementofthe part 53 in a vertical plane. Thesocketpart 53 is also connected tothe lug 46 by a lever 55. The upperend of the lever'55 is pivoted tothepart 53 at a point spaced outwardly from the pivotflfi arid the lowerend of the lever is pivotedfto the projectionllfi.

The releasing member 32 comprises a plate 56 extending in the directionoflength of the column, and positioned atthe outer?side oftheelevating-part L2. Asshownpar ularly in Figure 3 .of the drawings, theplate 5Hisprovided with sl ts 51 8 M531 r sp ct v re e ing he pjections. and 46. Also fth eleasing plate is fashioned with slots 59' anSilfor respectively receiving the lugs 49 and Theupper end of the platehas alaterally inwardly extending lug 6| which projects over the'djacent end of the elevating part l2 so as to be oyedas aunit withthelatter. A suitable operating leme 62 i secured to the releasing pla;-.56 adjacent the lower end inja Position, to --bec0nvenient1yengagedby afoot of -the user.

' Op r tion Assum n t at th W d e-parts f the jack preyiously descr eare in the tslei iv qsiii e shown in Figure 2 of the drawings, and thatit is desired to raise the lifting part l2 relative to the column H, theoperator causes the member 29 to be swung downwardly. The resultingforce is transferred to the wedge 37 through the lever 55, and since thewedge 37 is locked against downward sliding movement in the guideway 24,the wedge 33 together with the wedge 34 is moved upwardly in theguideway 2 3. Upward movement of the wedge 33 causes the projection 45to engage the shoulder 63 on the elevating part I! and moves the latterupwardly along the column I'l.

Upon completion of the above, the operator raises the member 29 and asa. result applies a downward force on the wedge 33 and a lifting forceon the wedge 31 through the lever 55. Since the wedge 33 is lockedagainst downward movement in the guideway 24, the wedge 31 together withthe wedge 38 is moved upwardly along the guideway 24. As shownparticularly in Figure 3, upward movement of the wedges 31, 38 causesthe projection 46 on the wedge 3! to engage the top wall 64 of the slot48 in the part l2 and moves the latter upwardly.

It follows from the above that successive movement of the operatingmember 29 in opposite directions causes the locking devices 36 and 3! toalternately move upwardly with a step by step movement. Inasmuch as theelevating device !2 is moved as a unit with the locking devices, it

' follows that the pad 21 supporting the part to be raised is alsoelevated.

When it is desired to release the jack, or in other words, lower theelevating device l2, the operator merely applies a downward thrust onthe part 62 connected to the plate 56. Slight downward movement of theplate 56 causes the upper walls of the slots 59 and 643 to respectivelyengage the projections 49 and 5!! on the respective wedges 34 and 38. Asa result these wedges are moved downwardly relative to their companionwedges and both locking devices are released permitting the elevatingdevice [2 to slide downwardly along the pedestal l I. the aboveconstruction to effect periodical downward movement of the elevatingdevice by merely successively applying a releasing pressure on the part62. In any case the releasing action does not cause the operating member29 to kick in either direction and endanger the operator. In fact theoperator may release the jack from a safe position with respect toeither the jack or the vehicle.

What I claim as my invention is:

1. A lifting jack comprising a base, a column supported at its lower endon the base, an elevating part supported by the column for slidingmovement lengthwise of the column, a pair of locking devices supportedby the column for vertical sliding movement relative to the column, eachlocking device comprising a pair of vertically aligned wedges havingadjacent overlapping surfaces at the inner sides inclined with respectto the path of sliding movement of the devices, abutment surfaces on thecolumn extending vertically in the direction of sliding movement of thelocking devices and respectively engageable with the outer sides of thewedges, means connecting the wedges of each pair permitting limitedrelative sliding movement of the wedges, an

It is possible with operating member respectively connected to theuppermost wedge of each pair for alternatively moving the lockingdevices upwardly relative to the column, and means on the elevating partrespectively engageable by the uppermost wedges of each pair to impart alifting movement to said part.

2. The lifting jack set forth in claim 1 in which a releasing member isrespectively connected to the lowermost wedge of each pair for releasingthe wedges and permit lowering of the elevating part.

3. The lifting jack set forth in claim 1 in which the wedges of eachpair are connected by a spring element, and in which a flexible stripextends between the overlapping wedge surfaces of each pair of wedge andhas end portions which project beyond the locking devices between theabutment surfaces and the adjacent outer sides of the wedges.

4. The lifting jack set forth in claim 1 in which the column has avertically extending channelshaped guide, and in which the lockingdevices are slidably supported in the guide one above the other.

5. The lifting jack set forth in claim 4 in which a thin flexible striphas the opposite end portions respectively ecured to one side of thechannel beyond the locking devices and has an intermediate portionrespectively extending between the overlapping wedge surfaces of eachpair of wedges to the opposite side of the channel guide.

6. A lifting jack comprising a base, a column supported at its lower endon the base and havin a vertically extending channel-shaped guide, apair of locking devices supported in the guide one above the other andslidable along the guide relative to the column, each locking devicecomprising a pair of vertically aligned wedges having adjacentoverlapping surfaces at the inner sides inclined in a directionextending transversely of the guide, spring means respectivelyconnecting the wedges of each pair, an operat ing member having one endportion pivoted to the uppermost wedge of the top locking device forswinging movement in a vertical plane, a lever having one end pivotallyconnected to the uppermost wedge of the bottom locking device and havingthe other end portion pivoted to the operating member at'a point spacedfrom the pivoted end of said member whereby swinging movement of themember in opposite directions alternatively moves the locking devicesupwardly along the guide, and an elevating part supported by the columnand connected to the locking devices for operation by the latter.

7. The lifting jack set forth in claim 6 having a member supported bythe column for sliding movement relative thereto and having portionsrespectively engageable with the lowermost wedges of each pair forreleasing said wedges.

8. The lifting jack set forth in claim '7 having a thin flexible stripextending between the overlapping surfaces of the wedges of each pairand having end portions secured to the column beyond the locking devicesto permit movement of the devices along the guide.

LOUIS SCHWEITZER.

No references cited.

